need help overclocking 2.4c

[softball]

for testing, I downloaded prime95v237 and ran it with default settings, I chose torture test and click ok but when i check task manager, it's not even showing 50% of cpu usage, it's usage jumps to 50% sometimes but goes back to 1-6% cpu usage quickly, but here are the results:

5:4 at 250/200 gives errors instantly in prime with these timings:
222-5 vdimm 2.8 vcore 1.52-1.625 all gave errors within 1-3mins
222-6 vdimm 2.8 vcore 1.52-1.625 same results
233-6 same voltages and results

1:1 at 220 vdimm 2.8 vcore 1.52 ran without errors in prime for 2hr 11mins before i stopped it on 3rd run of test 1.
1:1 200 with 222-5 timings vdimm 2.8 vcore 1.52 ran without errors in prime for 54mins before i stopped it.
I'm thinking since the memory can run at 200 cas222-5 and 220 cas233-6 in 1:1 it should work fine in 5:4 but it didn't. It doesn't make sense, overclocking at 1:1 using memory settings of 200 222-5 and 220 233-6 works yet when i use 5:4 at 250/200 or 275/220 with the same timings i used in 1:1 it doesn't work. I updated my IC7max3 to the newest bios, using hyperx 3200 2x512 in dual channel mode, set agp/pci to fixed, used NB PSB at 800 on all overclocks, left GAT on all auto and even auto/auto/auto/disable/diable but no success. Using a SX835II with 350PSU with +12 and +5 values in range. I've read most of the threads that apply to me but have no success. did i miss something or could my MB just have a problem with 5:4?

[Schneider]

Well u see theres this annoying problem with CH-5 chips on all 875p motherboards. They love 3:2 and 1:1 but absolutely hate 5:4 ratio. I'm having the same problem as u r just my RAM is HyperX 3500 and my mobo is the 8KNXP.
When u say the latest BIOS do u meant the 12 or the beta 13 BIOS?? If u haven't tried the beta BIOS u should coz its meant to fix that problem.

[shimmishim]

for the 50% utilization thing... run two instances of prime95 and that'll make that go up to 100%

as for the 5:4 and the errors you get...

i have some ocz pc4000....

after emailing ocz, it turns out that 5:4 really stresses the ram for some reason..

it can do ddr500 just fine 1:1 with 2.85 volts...

but when i try to run a fsb of 292 (which is the limit) and the 5:4 ratio which puts ram at 233 or ddr466, even with timings of 3-4-4-8, the ram still gives errors with memtest86....

that may be your problem..

also, i don't think any ram out can do 2-2-2-6 on the 865/875 chipsets...

i think the tightest timings are 2-2-3-6

oh well...

hope that helps!

:)

[softball]

well thanks for the suggestions, i got a new motherboard, the asus p4p800 deluxe using the same memory. the good thing is i can hit 3ghz at 5:4 using timings of 222-5-4 with default vcore 1.52 and vdimm 2.75 and performance at turbo with mam disabled. for some strange reason, enabling mam causes the system to get the blue screen error msg in winxp no matter how little of an overclock or relaxted the timings are using 5:4. i left prime running overnight, 1 prime doing memory and the 2nd prime working the cpu. had no errors. memx86 ran settings of 222-5 at 200 and 232-6 at 220 1:1 without errors for 4 hrs. i tried bumping the fsb at increments of 5 using 5:4, going from 265 down to 255 yet nothing would remain stable at default vcore. i went as high as 1.60vcore, after 7mins in primes there was one error. seems like i hit the famous 250fsb wall. i am statisfied with 3ghz but wished i knew if its the 250fsb wall keeping the system unstable at anything past 250, i just want the max fsb i can do at default vcore and i doubt it's 250 and not the 250 wall.